Colour-octet contributions to photoproduction via fragmentation at HERA

Kniehl, Bernd A.; Krämer, G.

doi:10.1016/s0370-2693(97)01126-x

Cited by 31 publications

(14 citation statements)

References 54 publications

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“…So various efforts have been made to confirm this mechanism, or to fix the magnitudes of the universal NRQCD matrix elements. Although it seems to show qualitative agreements with experimental data, there are certain difficulties in the quantitative estimate in NRQCD for J/ψ photoproduction at the DESY ep collider HERA [5][6][7][8][9][10], J/ψ(ψ ′ ) and Υ polarization of hadronproduction at the Fermilab Tevatron, and J/ψ production in B-factories. A review of the situation could be found in Ref.…”

Section: Introductionmentioning

confidence: 91%

QCD corrections to polarization of J/ψand Υat Fermilab Tevatron and CERN LHC

Gong,

Wang

2008

Preprint

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In this work, we present more details of the calculation on the next to leading order (NLO) QCD corrections to polarization of direct J/ψ production via color singlet at Tevatron and LHC, together with the results for Υ for the first time. Our results show that the J/ψ polarization status drastically changes from transverse polarization dominant at leading order (LO) into longitudinal polarization dominant in the whole range of the transverse momentum pt of J/ψ when the NLO corrections are counted. For Υ production, the pt distribution of the polarization status behaves almost the same as that for J/ψ except that the NLO result is transverse polarization at small pt range. Although the theoretical evaluation predicts a larger longitudinal polarization than the measured value at Tevatron, it may provide a solution towards the previous large discrepancy for J/ψ and Υ polarization between theoretical prediction and experimental measurement, and suggests that the next important step is to calculate the NLO corrections to hadronproduction of color octet state J/ψ (8) and Υ (8) . Our calculations are performed in two ways, namely we do and do not analytically sum over the polarizations, and then check them with each other.

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Section: Introductionmentioning

confidence: 91%

QCD corrections to polarization of J/ψand Υat Fermilab Tevatron and CERN LHC

Gong,

Wang

2008

Preprint

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“…Polarisation observables were subsequently predicted [283]. By analogy with hadroproduction, CO fragmentation channels were studied [277,339,278] but were shown to be relevant only for P T > 10 GeV, thus outside the region covered by the HERA data. Until the advent of NLO analyses including the CO contributions, the situation could well be summarised by Fig.…”

Section: ψ Photoproductionmentioning

confidence: 99%

New Observables in Inclusive Production of Quarkonia

Lansberg

2019

Preprint

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After an introduction motivating the study of quarkonium production, we review the recent developments in the phenomenology of quarkonium production in inclusive scatterings of hadrons and leptons. We naturally address data and predictions relevant for the LHC, the Tevatron, RHIC, HERA, LEP, B factories and EIC. An up-to-date discussion of the contributions from feed downs within the charmonium and bottomonium families as well as from b hadrons to charmonia is also provided. This contextualises an exhaustive overview of new observables such as the associated production along with a Standard Model boson (γ, W and Z), with another quarkonium, with another heavy quark as well as with light hadrons or jets. We address the relevance of these reactions in order to improve our understanding of the mechanisms underlying quarkonium production as well as the physics of multi-parton interactions, in particular the double parton scatterings. An outlook towards future studies and facilities concludes this review.

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“…Fragmentation contributions in photon-gluon fusion [120][121][122] exist only at the next order in α s and are suppressed for p t ∼ < 10 GeV. The cc[8, 3 S 1 ]-channel is insignificant for the direct-photon contribution, but dominates in resolved-photon interactions at p t ∼ > 5 GeV because it includes a gluon fragmentation component.…”

Section: Photoproduction Mechanismmentioning

confidence: 99%

Quarkonium production at high-energy colliders

Krämer¹

2001

Progress in Particle and Nuclear Physics

218

180

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The theoretical description of heavy quarkonium production at high-energy pp and ep colliders is reviewed. Predictions based on non-relativistic QCD factorisation are confronted with recent charmonium and bottomonium data from the Tevatron and HERA. Potential shortcomings of the present theoretical analyses are discussed, and the prospects for quarkonium physics at the upgraded Tevatron and HERA colliders and at the LHC are summarised.

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Colour-octet contributions to photoproduction via fragmentation at HERA

Cited by 31 publications

References 54 publications

QCD corrections to polarization of J/ψand Υat Fermilab Tevatron and CERN LHC

QCD corrections to polarization of J/ψand Υat Fermilab Tevatron and CERN LHC

New Observables in Inclusive Production of Quarkonia

Quarkonium production at high-energy colliders

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